1. Field of the Invention
Example embodiments of the present invention are directed to video scaling for transforming input images into output images having suitable dimensions. At least one example embodiment of the present invention provides a video scaler with an output memory and a method for reducing the size of the output memory for the video scaler.
2. Discussion of the Related Art
Various related art digital imaging apparatuses may be used to normalize digital images. For example, digital televisions, high definition (HD) televisions, personal digital assistants (PDAs), International Mobile Telecommunications 2000 (IMT-2000) terminals, etc., may utilize processes such as picture segmentation, magnification, reduction and/or smoothing. These processes may provide distinct images incapable of being shown by analogue imaging technique.
Image-scaling techniques have been used in applications for images received through cameras, for partial image magnification and picture-in-picture by digital image output apparatuses. With generalization of colors and motion pictures in mobile communication terminals, image-scaling techniques may be increasingly important factors in interfacing between standard video Coder/Decoders (CODECs) and Liquid Crystal Display (LCD) units.
For example, a CODEC may be designed for Quadrature Common Interface Format (QCIF) of 176*144, where 176 represents the horizontal pixel number, and 144 represents the vertical pixel number. The combination 176*144 may define the total size of the image. In another example, LCD units of terminal apparatuses may be manufactured with various screen sizes corresponding to dimensions and unit costs. In these related art examples, images output from a video CODEC may need to be enlarged or scaled down so that the images may be displayed on a screen of the LCD unit.
A related art video scaler may perform a scaling operation using a clock signal having a frequency higher than that of an output clock signal. An output terminal of the video scaler may be coupled with an output buffer or memory to deal with asynchronization between image data output from the video scaler and image data transferred to an output terminal of the image processing chip (e.g., a terminal coupled to a display unit such an LCD panel). Size of the output memory may be defined by ‘the maximum horizontal pixel number * image data size per pixel’ for output image data.
In operational environments lacking sufficient system resources for digital image-processing functions, various kinds of digital image-processing functions may still be implemented because of sufficient power supplies and product volume (e.g., digital televisions, Digital Video Disc (DVD), etc.). However, portable systems, such as IMT-2000 mobile communication terminals, PDAs, digital camcorders, etc., may be limited with respect to product volume, power supply capacity, etc. Therefore, implementing digital image-processing functions on these systems may be more difficult.